Talented three-year-old Sweet Leader has undergone a second wind operation.

“It’s a real shame because he’s obviously such a talented horse,” co-trainer Lance O’Sullivan said.

“We’ll wait and see how he does, but he could still be a Railway Stakes horse.”

Sweet Leader has won three of his five starts, including an impressive last-start victory in the Gr.3 Cambridge Breeders’ Stakes.

Meanwhile, stablemate Cha Siu Bao has been gelded since last racing.

“I’ve never seen a horse put on so much weight after that – he’s probably carrying 40kg more.”